1. Field of the Invention
The present invention relates to an optical device, which is provided with a tremble preventing apparatus, to correct trembling caused by a hand tremble and so on.
2. Description of the Related Art
Conventionally, an optical device, for example, a pair of binoculars, is provided with a tremble preventing apparatus for performing a tremble preventing operation by which a tremble of a focused image, due to a hand tremble and so on, is corrected. The tremble preventing apparatus includes correcting optical systems. When the tremble of the focused image occurs due to hand tremble, the correcting optical systems are driven from a position, at which optical axes of the correcting optical systems are respectively coaxial with optical axes of other optical systems of the optical device, in a direction and by an amount such that a movement of the optical device is canceled, so that the tremble of the focused image is corrected. Note that the position is referred to as a "moving center position" hereinafter. In the optical device, the correcting optical systems are initialized at the moving center position, before starting the aforementioned tremble preventing operation.
For initialization, the correcting optical systems are driven to the moving center position after a supply of a power is started and before a tremble preventing switch, for starting and stopping the tremble preventing operation, is turned ON. The driving of the correcting optical systems to the moving center position is not performed when the supply of the power is stopped.
If the optical device is a single-lens reflex camera, an object can be viewed through a finder while the power is not supplied. Namely, there is a problem that an actual object image viewed by a user does not coincide with a theoretical (desired) object image that lies on an optical axis of a lens barrel of the single-lens reflex camera.
Further, there is a telescope or a pair of binoculars including the above-mentioned tremble preventing apparatus. Such an optical device is provided with a single switch for both a power switch and a tremble preventing switch. When the optical device is mounted on a tripod and so on, it can be used with the tremble preventing switch, namely the power switch, being OFF, as the tremble does not occur. Accordingly, there is a problem that an actual object image viewed through the eyepiece(s) does not coincide with a theoretical (desired) object image that lies on an optical axis of a lens barrel of the optical device.